BT, TT and mixtures of BT and TT are known compounds which can be produced, for example, by the methods disclosed in U.S. Pat. No. 2,861,078 and by the method disclosed in U.S. Pat. No. 3,227,726. It is sometimes desirable to produce BT, TT, or a mixture of BT and TT having minimum color. To this end, a vacuum distillation is frequently used as a final purification step. It has been found, however, that crude triazoles contain volatile impurities which are color bodies, diazotizable impurities which are color body precursors, or both. Such impurities cannot be removed by vacuum distillation, because they are distilled with the triazole and impart color to the material immediately after distillation or, in the case of color body precursors, cause discoloration after the distilled product stands.